Statistical Investigation of the Fatigue Life Based on Small-Crack Growth Law

Abstract

Statistical analysis is necessary in evaluating the fatigue life of structures. In the present study, rotating bending fatigue tests were carried out on specimens with two small blind holes of a 5052 Al alloy in order to investigate the distribution characteristics of the fatigue crack growth life based on the small-crack growth law [formula omitted]. The crack growth rate in each specimen was determined uniquely by [formula omitted] therefore the crack growth life can be predicted by the small-crack growth law. On the assumption that the value of n is a fixed one and the value of C1 is a random variable, the distribution of the crack growth rate can be evaluated through the value of C3 in the relationship [formula omitted]. C3 follows a Weibull distribution approximately. The calculated distribution of the crack growth life based on the small-crack growth law and the distribution of C3 was in good agreement with the experimental results. © 1993, The Japan Society of Mechanical Engineers. All rights reserved.